1. Field of the Invention
This invention relates to a recording method using recording liquid. More particularly, it is concerned with a method for recording images on a recording material such as paper, resin film, etc. with use of recording liquid which is generally called "ink" by means of an ink jet recording system or various writing implements such as fountain pens, felt-tip pens, and so forth.
2. Description of Prior Art
The ink jet recording system is such one that performs image recording by forming ink droplets and causing a part or whole of the droplets to adhere onto a recording material (hereinafter simply called "recording paper") by means of various ink ejection systems such as, for example, an electrostatic attraction system, a system which imparts mechanical vibration or displacement to ink by use of a piezoelectric element, a system which heats ink to form bubbles and ejects the ink droplets using a pressure of the formed bubble and others. In case use is made of writing implements, the recording ink is drawn out through the capillary bore and placed on the recording paper, as has been well known.
For the ink to be used in such ink jet recording system or writing implements, there may be exemplified, in general, one composed principally of a water-soluble dyestuff, water as the solvent to the dyestuff, and glycols as the desiccation-preventing agent. As the water-soluble dyestuff, direct dye, acid dye, and basic dye are used preferably, since they are excellent in their fastness and color tones, when recorded. Since those dyestuffs are produced for the purpose of dying textile fibers, they inevitably contain various impurities such as, for example, inorganic salts like sodium chloride, sodium sulfate, etc., and metals (ions) like calcium, magnesium, iron, silicon, etc.
When the recording ink is prepared with such dyestuffs containing various impurities as mentioned above, unfavorable situations would arise, as will be mentioned in the following. That is to say, solving stability of the dyestuff in ink becomes poor to bring about agglomeration and sedimentation of the dyestuff; and, when the ink becomes dried at the ink discharge orifice or in the vicinity of the capillary bore to change its composition, deposition of salts is brought about. These phenomena would be the cause for clogging the ink discharge orifice and the capillary bore, which must be avoided with utmost of the care in the image recording by use of the ink jet recording system or the writing implements. Although various proposals have been made as the measures for preventing such clogging, no perfect solution has yet been found.
When the ink is of a kind which tends to clog the ink discharge orifice, etc., the dyestuff concentration in the ink must be made low with the consequence that the density of the recorded image is not sufficient and devoid of its required quality, and its light fastness becomes also poor.